1. Field of the Invention
The present invention relates to an image processing system for processing image data and displaying an image on a display device. Particularly the invention relates to the image processing system and an image processing method which display an enlarged partial image (magnifying glass function) overlapping a full image.
2. Description of the Related Art
Doctors photograph patients so as to obtain X-ray images and view the X-ray images so as to know conditions of the patients.
Conventionally, after X-ray devices photograph chests to obtain X-ray images and the images are developed on films, the images are viewed by using schauaukasten. Digital X-ray devices are developed, however, so that X-ray images are captured as digital data by computers. For this reason, X-ray images are recently displayed and viewed on monitors.
According to digitization of X-ray images, the contrast of the X-ray images can be changed on the monitors, and the X-ray images can be enlarged. When the X-ray images are enlarged, in most cases, a ratio is changed by using pointing devices such as mouse devices of computers. In this case, the images are normally enlarged and reduced at centers of the X-ray images. Further, it is publicly-known as the so-called “magnifying glass function” that a specified partial area of an X-ray image is enlarged and is displayed so as to overlap a full image.
In the case where a part of an X-ray image is displayed by the “magnifying glass function” so as to overlaps a full image, however, when the original full image is tried to be zoomed, the following problem arises. FIG. 12 is a diagram illustrating a conventional problem example in a portion of the “magnifying glass function” obtained by zooming a full image. In FIG. 12, a left side shows an X-ray image before a zoom process, and a right side shows an X-ray image after the zoom process. A reference numeral 20 designates a monitor screen, and it is a screen of a display device for displaying an X-ray image. A numeral 21 designates a full image and it is an image showing a full X-ray image. A numeral 22 designates an enlarged partial image. A part of the X-ray image (full image 21) in a predetermined position is enlarged by the “magnifying glass function” and is displayed with it overlapping the full image 21. A numeral 21′ designates a full image after the zoom process (hereinafter, zoom full image), and it is an image which is zoomed at a center of the full image 21. A numeral 22′ designates an enlarged partial image after the zoom process (hereinafter, zoom partial image), and it is the enlarged partial image in a predetermined position of the zoom full image 21′. Numerals 23 and 23′ designate circles that represent a change in a position of partial enlargement on the full image 21 by the zoom process.
As shown in FIG. 12, since the full image 21 is zoomed at the center of the full image 21 displayed on the monitor 20, a positional relationship with the enlarged partial image 22 cannot be maintained. As a result, the position of the zoom partial image 22′ on the full image 21′ after the zoom process is partially enlarged. As represented by 23 and 23′ in FIG. 12, the zoom position 23′ shifts from the originally enlarged partial position 23. Further, due to this problem, a user should change the position of the magnifying glass after the zoom process, and move a visual point. As a result, user's thinking is interrupted, and thus the operating efficiency is deteriorated.